SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a5789061681b3e90a0a9098100ee0e3fb58fe56bfbfe0085fe348494d42560c' 
  AND token = 'tl1IDwxsZUqTlupVPSCQqmgdXVOdbMjlGhgjKmha7XY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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