SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7cb379519af4dd5a9469f2c719a6fbba82c4a769cde2a3a1dafbe8e748b861e' 
  AND token = 'Fdzb7LajCqzxawVLd13DgtFfofDje4WIdO40f9UoMoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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