SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a00ee239f14199ca3184b7240a1ef3bee1383ed893996c73c083b214836ae54' 
  AND token = 'Mvvs2ojyODne9VSmOgFYI0xDhSy+IW9wXE2gSx770Lo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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