SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6858b71778743a6ffca04b3d1650eb52d3854df6803d7af5f27a8f7dd6477278' 
  AND token = 'u+Ei7FIqSNtqcukzB54+L+k5zV5T69YHrqS6xE9vcEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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