SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3c44c23037e9de6a78cc30ef3479de2313007432bac9f0cb2efab53e6332355' 
  AND token = 'lm7jP/skMjL9AyhPWGwpci9eatg29rOQjyj/jBs+fik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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