SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a8fd931bb1ff207de89040d37e315db7bf2d750f3e5e811b5cfaaa128c226b1' 
  AND token = 'g7tMHOEA41of/eaN321jk6yofwoTtWweTeBrzy7Wiak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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