SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b496e9d6c70d9b22a0611be40d5ce188cd26db715d0b28539d58f453e244f963' 
  AND token = 'ynlwIEaChQBBAr94yRkKEiHeYgTKiJLYO74pbqIJ/Z4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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