SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ce93dde8a4c0548f7458a2ffeabbe6c43eeaa578bc5e995edff101f90e87a70' 
  AND token = 'FkEHsvC8+WubLizYhW5A21LxIg13NtvHkv0astzwKog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}