SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54bea9157620b89c5a77e253fb728203149fd064f46ea386463930c596c74ee0' 
  AND token = 'OH0uKjH9uNm5Iy0+nuIZXaMuy0dd9BBBIjbZfhXjcqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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