SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0e2c672d3ac82493e10b84bb749918bb6153a6e1a27744da0679d8ddc836162' 
  AND token = 'Z5GcGHSff9UvHAclM3o9qaOj+nxnM5G/nqLIU4wW+KM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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