SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0200ee66e822190af965245c944e57db8592e5041d39e2afda574ebbd39ed4da' 
  AND token = 'dYkRJnMt8LWaw6k+RSQ7+gc3KaXnlSFDreHs9vWCDWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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