SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6af3251f3e61ac5d628336fcc1a353d493728021a587ef6b97dd8ee253f0c99d' 
  AND token = 'JfjnefkbhQZv1DrnwLOQdhxeIjqR9j6mArNR2Zj9KhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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