SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f16216d1f65d6fc99ccc078b256cc6c4df4fe8f3584973d384878989407b4699' 
  AND token = 'v0eZR8jG92RJIU3oUXsNC4Yhwl3LatCnCySrTRDCNSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}