SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bc79dd8544feeaa6d792115c056a9829a127c123860d3a26f00ee0d73644818' 
  AND token = '4rvGiKb/CXf0mVMF1Xl5XS2i5qygISCklJx9EbD4hPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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