SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '91bf74b43f2fffda1daf3d31a3f6cce02bd34c1b936865bb65750b732164ee71' 
  AND token = 'uqg/KJ3QEskMVFDFMVmBoKOt9CnVVNia/FbrPAOWCxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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