SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3af0e50c1a8c4695445276bf2269cb45b8062050ee0010d2e0bc24e103f0998' 
  AND token = 'wLlpR+imkWiQUZQDhKp5kQAsLn1qs1V3EIG99ZmknL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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