SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2c4ba2155280eac7d4efb29346d4ae88e18b290ea2d0f915f6e8a620bcee690' 
  AND token = 'uIELvTSxldPc2iFSwgc4tepglJxUlG0x130oUUVRbsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}