SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29f21c1aca03447b4d0cfbddea9d3fc3c89f4a86ad179719fdf3c97c598ce3e6' 
  AND token = '2XhqbNbv/mVAaZCPHFlRIrfCj3PwbXE74rQzz4WQJgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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