SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b54bfb9ef4040079fa6374d0706d186f594e7093e15e30500aafce504721c19b' 
  AND token = 'FJnkig/twWcIsDqqz2H2zdCE061c+jsJZJvNvjOiOZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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