SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c454beae40f238b35fc5d40101d13a760c1fdf6a495e207d7e98929a3365eed7' 
  AND token = 'VZVPtGffSp5LuwI9n3sWBfH2BBOkYvCs9/RBTHeidYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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