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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9c3cb5a31451c1cef8fb24e29c6f718e108fb0b4d0549c82fe2fcef7b1acc6e' 
  AND token = '5nyo7QkwrdxarYZQpWLoPkuVxNgpmtuoint2yFG9PyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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