SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '321f2324fce20763cd8970615518a74a6b3fd67bc977caf4ba690ba180ecaeb7' 
  AND token = 'SRBMYjTvVkWEe6aAVOL+vuoXy52jeqCk2ct1lbi4dIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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