SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c44af07d19a784a0b34a3cd165659d1d2f27568278e9b8f0937f3b98102b145' 
  AND token = 'DY/IXjG2D0FpBejQLVN+HNwFAlT3HMeXMlAuEYf6iV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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