SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7cb4fcd7fff68b3eaf049a1085321a0b486714994636a6486a6e85fc080f09a' 
  AND token = '2OfHZjgGtb7ij482soGbWfAfGc2wzrWpNI5OMlePcKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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