SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd28fe33ef779adb5888551a054392b5af88e3f59ea729ebc5877a0dd5e925ce' 
  AND token = '2TACnBeAGBwQX92FzbklBwNwu7FIjZl+2zrwF0q/qmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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