SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d89d88a0133e590771f1bb602477ef89ffca0dcd97eaaa30152549a25d94cf8' 
  AND token = 'mzM3jxMeV6Od+Bw3v1zPqFKdPo2hiZU9jr775SVwOZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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