SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd298e8a406bffbe1ba7caee44d1fea1150ed0e1e29044f3e840f827e4cfc6f76' 
  AND token = 'pMSCUMphnrEDBysMfBQguXK+/YaaGoKcSTE8fPHGC50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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