SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3451a8efac1a2e4e437f0b4c5581825798c9279855a1fed7f559cfcb2eba068' 
  AND token = 'w8wPmKKrp/k4/EJf5qYIHMkR/Lmu+PV8XXBsoFFCkrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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