SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2866a6b2ba293ecb1af320a5ac9bd823de35a6aa5b50231bc2ebf4328378b575' 
  AND token = '7llBLVLNdzhKI0bupuAph89QtY9OfrmkBGNFmay6wTQ=' 
  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"
    }
  }
}