SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5782131d1d11507b95aa7df43119ac108bdd8fee66621918e18881ffafb1351' 
  AND token = 'InLA+J175rliXIVFf2LThdt/Z2UBk2j5T/ncsKUnPoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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