SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '29a7efe002e0e62564b99c8a8535b176b26cf231af6d1005adc1e63ae2c4f8e6' 
  AND token = 'SvGTHOwL+4JbiAwpxhgdDkNZ7rxXkCeUUQYL10UfIr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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