SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66e478ba7b10fcf5660ffbded35809784c030abadd51b22a00f35b46ae9ccbc3' 
  AND token = 'RKaJ6MwsBHQedfaBOib+CFzSC68fPsy5KC2v/4cV50M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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