SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f2db66bf56955b98fe088399d74e43226090db9d598fe1f86cecb59cda216ed' 
  AND token = '6uxwRC/XEbFkfKnwrM0SPZVBncy2mfSEniqXohwHJ8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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