SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a2d3d1beaa7395f65479783e490d7a5d76452f849410408b082cacf86c40ca1' 
  AND token = 'OQjYoElRU0/HCL2gLBJTtTp/Y7uUlhIGzy0VpNghJGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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