SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '965823d4b425cf4fd9a6862a07b4d82ea257757344a3ee4ba6bc4b7e82f8bcac' 
  AND token = '8ZcgnpcAOoC0zAeP9dDOQWAiRoFUJDyS+xuf5HzNEDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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