SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97e7449bc195ddcf8df94d96200cfc757003c635185f448f8d728a0ff8092425' 
  AND token = 'xNuWI0rSPr2PHg54XKMZwmbMCsh0OWAhW5n2ButS5g8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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