SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eff5c1ea8bca8622c5015c7ab76ca2f97bb6cbc554882395247d043cd5833cfb' 
  AND token = 'j/SGtDMU5Tl/f7ZayzKgMXh76VCyWg7ughHAEHoMiB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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