SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd071871bff0e5376ac20d725a2ff68e6039b29a290f6423cc5733faa62fa32be' 
  AND token = '/cRM4WAVCSxLf0pQf6TBQmAU0q7pzUKexrq1PCv4QwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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