SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83b71da8cf4bdbb2d99864f78c75220bfcdcfd72a2c09f7f4fe18077094d583e' 
  AND token = 'SCNxydegngrTCoR1+Ia5+YiAZGYgAk3Og6Ru8qcMHt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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