SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67948797ab657d4eba184732fbcbea747086464375d5bbe19abe3c5c2ec4b0a6' 
  AND token = 'VkWB2tRCQz9PKEF02vGYPchPMcN/bdznswlcnuz6fZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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