SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8810a092d00fe5ed5270108a70a3ab63842ebc205df187348bfd8ac76f6e3637' 
  AND token = 'rA2mCIaLhAErqwMPKGyHIwMXSXASyjuUqtUtiaAU0Cs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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