SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56da1d4847f3c46278d62717df81aeea842c16272eee816b3a2a0b2fc7575fe2' 
  AND token = 'EdremTFjbzvSnDgc21vfAd8sl8jRvP8o4b5FX2+9d7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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