SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b18c4d64379fe7e2968a61e27b56b27d97f14c855ea8c3a8552056d00707f7f4' 
  AND token = 'h9RsWGWWwMxHz+YAJkx8vDPYB0/xceCkV55pGWApWEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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