SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3457f7911393e0f65a4689745cb0f52d6f831d9eca5774b79c356fac49ae4f52' 
  AND token = 'fv/goWJPYTng7qUNRvmJzkuexAOVnxsgKRP4340DU8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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