SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3bcf531774372f8c01a632010153695430fef83ad69b65604bedd14c671b10a' 
  AND token = '2G1/cgP8ROE+Ux3iSNAL52bFXWKlKY9AsmEqIlSDGhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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