SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da458d27de2dce297ee31188d7e784f9b37c6ded25e78d1f8d175fbde45b69d2' 
  AND token = 'aM3AKuk4y1Ktrm398DTewuM3w5hyGnQ3NzCHpB5bc2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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