SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9985dbb869515c1c89f07c5e8f56b57697cdaf8a09d731ebca6c406314598ab1' 
  AND token = 's3RoFrGsImIKhjZwOZcp6DefpQKRyZvxyp2pqErkUgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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