SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e06c3ab7ed7d0ce1fcf170924153aad45115098820d861cee940fedd498343b8' 
  AND token = '5SvAavPiqlXL1/Nt4TjEsey73Qxd7ESdLgpNwL1ElOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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