SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f7dee33be68f52c53cc023fe6f920fc250b7b4f8224570c610233285533d2a1' 
  AND token = 'GGJ5NIrOQgimyhtW2JdZ/jXARwBk6MRA7KHcUXmwYW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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