SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '594dafbcf704ac5b68a7bc30498a35f5f629bf5e3579e33bd845731b61401272' 
  AND token = 'F5jW4jl6dZRNzQWVRgNQE/jNiFWOhq/jmRP6OzUur4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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