SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '870364ef8b3991d667402259030d3a0f5675f64d8965e84cd211d0f3baa0c070' 
  AND token = 'YNVDgPR6Q4Y49GjbXH4uPqhfyM/i2NKWMuAHQcCEUWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}