SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b896f4b46e10f2696e54474dce403fb20dcae483467738bf5d4a31c25e8af0dd' 
  AND token = 'WQryoPFuzUKIIsC2YONuL/EGAyvv2U4VS+ION+to8dI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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