SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b0f3d49e2252e6724f3fa2cad9534fe8854408943d290571de4fe9d7459dc1b' 
  AND token = 'ajGSHRe0fzM5hbCWmmf3og9KHjF2tiSZrJdVZ4FZIwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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