SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b66728ae959df470cb40de73360b5641827938cf7d61d751c5178d8df6f4e03' 
  AND token = 'J+n+r/MoN3FZYTF7vP8VXL9QNBHilEbJJnje+KhsO68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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