SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a07b0a988d688105d04af5e0e3655bc898fbb9f89b878390baee58e4382e0d20' 
  AND token = 'qiJ5MSswhqWpGT3JQnfMCEegmOCywMhZs7K0xobweKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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