SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12d4137a37abf0e7956e5ada282af7536044adc024a8e4598fd2335aa65dafdc' 
  AND token = 'aIUvpcSKIKxo3KCc5JQ/FYU02hw72pzZhndSTdLAdmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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