SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f7235283617ef5c5a88990fc0d4dc9f408efe7f5875b7199f20f11ea451c360' 
  AND token = 'hqc6vGPPYgabPcurs0xYHznpNpYU8nyGN2YzMeG3s/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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