SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9b9365f37bee7e3c1e52b1eff4406d985c37f0ec8c5debb8449c5b9833714a8' 
  AND token = 'JAewYjtrBsIy7fSLDi8rw6fNiqrovbGuE/9sbZSOTSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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