SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1839b8e2333c9817e1ee136fee54e2142dbc528993c2ffd5a6befb4c207bfd90' 
  AND token = 'Xn+ITlj/aPA/UhhmamrXdk2fSB8VBqjwuJhhjJYzlks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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