SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb6b89da6b5d41bba45c96ce2f42a566be47b32e09cdafc243dbe8f450237f5d' 
  AND token = 'qV81HTpcCsT9DCanYXcjyie/KrMF5goZHbLAqaHCM54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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