SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ab618fbd7733924e70c83c0b972983be35d3c6376c715563382d3ea110c6b63' 
  AND token = 'LKzUhJ/rBFb7mbHGP1bhLqDIOaU7Wov1Ing+YUfGsi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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