SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ecfa50d33685c0cb96b907814c18a61f4e176a0826f6017bffab1a588fd3f037' 
  AND token = 'SZqUAxwzzZvGJyXpqDupNE+faij6XsOosuju+Q2+pRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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