SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fac51d839f5772a17a05e3b187203a84d12ad1c2178512e4ac54217debd8dfb' 
  AND token = 'MYnBxlduXP0CXPQspfT4j9s1117DP3E+lFxBNQEaOeE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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